Drilling apparatus

ABSTRACT

Drilling apparatus adapted for setting electrical conduits in place under roadways comprises a bit mounted in a subassembly for movement along the axis of drilling as well as for rotational movement, a spring-operated hammer within the subassembly adapted to impart a blow to the bit in the direction of drilling, a cable attached to the hammer and extending through conduit sections being set in place to a hydraulically operated mechanism for withdrawing the cable against the force of the spring and suddenly releasing the cable.

United States Patent [72] Inventor Donald E. Lawlis Buckley, Wash. [21] Appl. No. 881,027 [22] Filed Dec. 1, 1969 [45] Patented Aug. 17, 1971 [73] Assignee Del-Guy lnc.

Buckley, Wash.

[54] DRILLING APPARATUS 5 Claims, 6 Drawing Figs.

[52] US. Cl 173/88, 173/119,173/133 [51] Int. Cl E21b H04 [50] Field of Search 173/19,53,

[56] References Cited UNITED STATES PATENTS 9/1921 Rotinoff l I I5? 84 i 1,612,062 12/1926 Scott 175/395 2,214,970 9/1940 Mooney 175/322 2,349,033 5/1944 Elliott... 175/394 7 2,438,777 3/1948 Dean..... 173/119 3,312,293 4/1967 Cutler 173/119 Primary Examiner-James A. Leppink A!!0rm'yJnhn F. A. Earley ABSTRACT: Drilling apparatus adapted for setting electrical conduits in place under roadways comprises a bit mounted in RELIEF VALUE RESERVOIR PUMP I as

PATENTED AUG] 115m 3 599' 731 SHEET 3 OF 3 INVENTOR DONALD E. LAWLIS 1 442 4 ATTO R N EY S DRILLING APPARATUS BACKGROUND OF THE INVENTION This invention relates to drilling apparatus and particularly to apparatus for driving pipes or electrical conduits underneath roadways and the like.

In the past, it has been necessary to tear up and repave roadways in order to set pipes and electrical cables in place underneath them. Various devices have been invented which avoid the tearing up of the roadways. Pipe drivers have been used in which a bit is fastened at one end of the pipe to be set in place, and a succession of blows is delivered by a hammer at the opposite end. Such systems have met with some degree of success, but the force of the blow on the bit is very much reduced as a result of longitudinal compressibility of the conduit. Furthermore, bulky hammers are necessary to impart a sufficiently strong blow to the conduit. A pipe driver of the type which operates by the imparting of blows by a hammer to the conduit is disclosed in U.S. Pat. No. 2,599,989, issued June 15, 1952 to John L Haston.

Another approach to conduit emplacement is exemplified by burrowing tools of the type disclosed in U.S. Pat. No. 3,407,884, issued Oct. 29, 1968 to Kaximierz Zygmunt. These burrowing devices generally contain pneumatically operated hammering devices. They are not connected to the conduit being set in place or to any other from of drill stem, but have a pneumatic cable as the only external connection. When the burrowing device travels underneath a roadway, it produces a passage through which a conduit may be later inserted. The problem of steering these burrowing devices has prevented their being accepted for general use in producing horizontal underground passages.

SUMMARY OF THE INVENTION In accordance with this invention, there is provided a subassembly, at one end of which there is provided a bit mounted for limited movement in the direction of drilling. Within the subassembly, there is an anvil rigidly attached to the bit, and a hammer which is urged by a spring toward the anvil and in the direction of drilling. A cable, attached to the hammer, extends from within the subassembly, through the conduit sections being set in place, to an external mechanism which is adapted to withdraw the cable under the action of a hydraulic cylinder and to release the cable suddenly in order to allow the spring within the subassembly to urge the hammer against the anvil. A force is constantly applied through the external mechanism to the conduit sections, and it is this force, rather than the blows of the hammer, which moves the conduit sections. The blows on the bit cause the bit to cut an opening ahead of the subassembly and conduit sections, and the subassembly and conduit sections are moved into that opening.

The principal object of this invention is to provide a relatively simple apparatus for setting pipes and conduits in place, which is capable of very rapid operation, and which is capable of cutting through underground obstructions such as rocks,- tree roots and the like.

Other objects of the invention will be apparent from the following description read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevation ofa drilling apparatus in accordance with the invention;

FIG. 2 is a fragmentary perspective view of the drilling apparatus showing details of a mechanism for suddenly releasing the cable;

FIG. 3 is an axial section of the subassembly at the bit end of the drilling apparatus;

FIG. 4 is an end view of the bit, as viewed from the righthand end of FIG. 3;

FIG. 6 is a perspective view of the cable-withdrawing and releasing mechanism showing auxiliary apparatus for providing hydraulic power to the hydraulic cylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 show a framework made from a pair of angle irons l and 12 arranged opposite to each other and held in fixed relationship with respect to each other as a result of the fact that both are welded at various points to a large-diameter metal tube 14', welds being indicated at 16, 18, and 22 in FIG. 1, and at 24 and 26 in FIG. 2.

A bracket 28 is bolted to angle iron 10, and a similar but opposite bracket 30 is bolted to angle iron 12. Between these brackets, there is welded a trigger block 32 which has a passage extending through it, an opening at one end being indicated at 34. A horizontal projection 36 is provided at the top of block 32 at one end, and a clamp 38 for securing a cable is held down by bolts 40, 42 and 44.

Cable 46, which is held underneath clamp 38, is wound over a sheave 48, and extends through tube 14. This is preferably a metal cable. Sheave 48 is rotatably mounted between a pair of plates 50 and 52, these plates being held together by bolt 54 on which the bearing for the sheave is mounted, and by virtue of the fact that they are both welded to a solid rod 56. The welds between rod 56 and plate 52 are shown at 58 and 60 in FIG. 1. A ring 62 is fixed to rod 56 to provide an abutment for spring 64, which acts as a shock absorber, as will be apparent from subsequent description. Angle irons l0 and 12 extend along the sides of plates 50 and 52 to guide the sheave assembly, the innermost edges of the angle irons being separated by a distance just sufficient to allow the sheave assembly to slide between them.

A hydraulic cylinder 66 is pivoted at one end between a pair of blocks including block 68, which are mounted respectively at the ends of angle irons l0 and 12. Cylinder 66 can rotate about pivot 70 in a vertical plane. Its internal piston is connected to operate a rod 72, which can be forced in both directions in a conventional manner by operating the spindle 74 of a conventional distributing valve 76, which is connected between the cylinder 66 and a relief valve 160. Fluid under pressure is supplied to the distributing valve through the relief valve by a supply pump 78. The cylinder has two hydraulic lines and 82, which are respectively connected to ports 84 and 86 of the distributing valve. It will be apparent that, if the spindle 74 is moved to the right, hydraulic fluid, entering port 83, will be delivered through port 84 and through line 80 to the hydraulic cylinder. Hydraulic fluid on the other side of the piston of the hydraulic cylinder will pass from the cylinder, through port 86, and through exhaust port 88 to reservoir 90. If the spindle is moved toward the left, hydraulic fluid will enter the cylinder through line 82 and will leave the cylinder through line 80 in a similar manner.

Rod 72 is provided, near its end, with a follower comprising a transverse triggering pin 92, the opposite ends of which are adapted to ride respectively on camming release surfaces 94 and 96, which are provided respectively on the ends of brackets 28 and 30. The end 98 of rod 72 normally abuts the end of rod 56, which extends through opening 34 of the passage in block 32. It will be apparent that, when rod 72 is extended to the left, rod 56 and sheave 48 are pushed to the left so that the cable 46 is withdrawn leftwardly through tube 14 at twice the rate at which rod 56 is moved. When pin 92 comes into contact with the inclined cam release surfaces 94 and 96, its end, abutting the end of rod 56, is moved upwardly until the end of rod 56 is released or disengaged. Rod 56 then moves toward the right allowing cable 46 to move to the right through tube 14. The end of rod 56 passes underneath rod 72.

Projection 36 limits the upward swing of rod 72, and springs 100, which are mounted on bolts on either side of the cylinder 66 above plate 102, absorb the shock of clockwise rotation of the cylinder as disengagement of the rods takes place and constantly provide a force tending to push cylinder 66 in a counterclockwise direction so that the return of rod 72 to engagement with the end of rod 56 is independent ofgravity.

FIG. 3 shows subassembly 103, which comprises a cylindrical member 104 having a cylindrical internal passage 106. An end member 108 is threaded onto the end of member 104. Member 108 has a central opening in which a rod 110 is slidably and rotatably mounted. One end of rod 110 is secured to a cylindrical anvil 112, which fits slidably in passage 106. At the opposite end of rod 110, there is provided a bit 114, the shape of which will be apparent from FIGS. 3 and 4 when viewed together. Bit 114 is essentially the frustum of a cone from the opposite sides of which two elliptically shaped surfaces have been cut, followed by the imparting ofa 90 twist to the tip 116. Surface 118 is substantially conical in shape, and surfaces 120 and 122 are the surfaces which were elliptically bound planes before twisting. Tip 116 forms a cutting edge, and the twisted shape of the bit causes it to rotate as it is moved forwardly. The rotating action enables the bit to cut through rock efficiently.

Within passage 106, there is provided a heavy hammer 134 which fits slidably within the passage, and which is adapted to engage the face of anvil 112 to move the bit 114 forwardly. A heavy spring 126 is shown held in compression between hammer 124 and the end 128 of a closure 130, which is threaded into an end of passage 106. Threads are provided at 132 for connection of closure 130 to conduit sections. Cable 46 extends through a passage 134 and through the spring, and is attached to hammer 124.

FIG. shows the manner in which the conduit section is connected to tube 14. A tubular member 136, having an outer diameter slightly less than the inner diameter of tube 14 is secured in the end of tube 14 by welding. An annular member 138, which is integral with member 136, is provided with a central opening 140, through which may pass cable 46. Con duit section 142 can slide into member 136, the inner diameter of member 136 being slightly greater than that of the conduit section. Member 138 provides an abutment preventing movement ofconduit section 142 to the left.

Conduit section 142 is provided with female threads at 144, and with male threads at 146. Threads 146 engage threads 132 (FIG. 3). Threads 144 may engage threads corresponding to threads 146 on additional conduit sections which may be added during the operation of the drilling apparatus.

P10. 6 shows the drilling apparatus in operation. The apparatus is shown being used to set conduit in place underneath a roadway 148.

As mentioned previously, the conduit is pushed through the earth by a force which may be applied constantly. In FIG. 6, the pushing force is applied, for example, by a winch, through a cable 150, which passes over a pulley 152 anchored at 154, and which is fastened to the mechanism by attachment of its end to a yoke 156. A carrying handle is provided at 158.

It will be apparent that the elements of the pumping mechanism, including pump 78, reservoir 90, relief valve 160 and distributing valve 76 are identical to the elements shown diagrammatically in FIG. 1.

The spindle of the distributing valve 76 is operated manually by a lever 162, but may be alternatively operated by well-known automatic means as well.

While the hydraulic system described has been found advantageous for the purpose of effecting withdrawal of the cable connected to the hammer in the bit assembly, various other devices may be used including pneumatic and electrical actuators.

In operation, the apparatus is first set up with a single conduit section 142 connected between subassembly 103 and the driver mechanism. The bit 114 is held against the vertical wall 164 of an excavation at the side of the roadway by the force applied through cable 150. The hydraulic cylinder is then operated repeatedly, pushing rod 56 rearwardly to withdraw the hammer 124, the hammer being released each time by the action of the cam surfaces 94 and 96 which raise rod 72 to clear the end of rod 56. Following each stroke of the hammer against anvil 112, the bit moves forwardly in the hole being produced, and is immediately followed by movement of the subassembly and the conduit section into the hole under the pushing force applied through cable 150.

After a large part of conduit section 142 is in the hole being produced, another conduit section may be added. This is accomplished by loosening clamp 38, releasing wire 46 and withdrawing cable 46 from the driving mechanism through the opening of member 136. The cable may then be fed through an additional conduit section which is then fastened behind conduit section 142. The cable is fed through tube 14, over sheave 48 and again clamped underneath clamp 38. The added conduit section will be in place in member 136, and the cable should be tightened before clamping so that all of the motion of the actuator piston is transferred to the hammer. As each conduit section is moved into the hole, additional sections may be added in the manner just described. When the bit finally breaks through the wall of an excavation at the other side of the roadway, the cutting action no longer takes place, but the pushing force is applied until the subassembly completely clears the hole. The subassembly may then be detached by disengaging threads 132 and 146, and cable 46 may be used to pull electrical pushing through the conduit.

It will be apparent that, when drilling through relatively soft earth, the hammering action of the bit may be unnecessary except to cut through rocks, tree roots and the like, since the pushing force applied through cable may be sufficient to move the conduit. When rocks and other underground obstructions are encountered, the hydraulic system may be put into operation so that the simultaneous hammering and twisting action of the bit will effectively break up the obstruction.

It will be apparent that various modifications can be made to the structure of the apparatus disclosed, and that its uses are not limited to the setting of conduit in place horizontally. For example, the apparatus may be used as well for vertical drilling.

lclaim:

1. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end ofa conduit a bit,

means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis of drilling,

a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling,

a first means urging said hammer in the direction of drilling,

a second means for pulling said hammer against the force of said first means and for releasing said first means to cause said hammer to impart a blow to said bit, wherein said second means comprises a linear fluid actuator, a cable having one end connected to said hammer, means for fastening the other end of the cable to the conduit and a reciprocable sheave movable by said actuator, said cable being wound around said sheave between said fastening means and said hammer.

2. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end ofa conduit,

a bit,

means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis ofdrilling,

a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling,

a first means urging said hammer in the direction of drilling,

a second means for pulling said hammer against the force of said first means, and for releasing said first means to cause said hammer to impart a blow tosaid bit, wherein said second means includes a fluid actuator,

means for pivotally mounting a first part of said actuator,

cam release means mounted adjacent to said fluid actuator for releasing said second means,

a follower on a second part of said actuator which is movable relative to said first part, said follower being engageable with said cam release means, and said follower and cam means being so related that said second part moves angularly about said pivotally mounting means as a result of interaction between said cam means and said follower through at least part of the range of operation of said actuator, and

means engageable by said second part of said actuator for effecting withdrawal of said cable against the force of said spring means, the last-mentioned means being arranged to be disengaged by said second part of said actuator when said second part moves about said pivoting means through a predetermined angle.

3. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end of a conduit,

a bit, 7

means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis of drilling,

a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling,

a first means urging said hammer in the direction of drilling,

a second means for pulling said hammer against the force of said first means, and for releasing said first means to cause said hammer to impart a blow to said bit, wherein said first means comprises a spring located within said subassembly, and

said second means includes a linear fluid actuator comprising piston and cylinder element one of which elements is adapted to be connected at the other end of the conduit opposite said subassembly and the other element being movable with respect to said connected element through a range of positions,

a cable connected to said hammer,

means engageable by said movable element for pulling said cable in response to operation of said actuator to withdraw said hammer against the force of said spring, and triggering means for automatically and instantaneously releasing said cable and allowing movement of said hammer by said spring when the movable element of said actuator reaches a predetermined position in said range,

4. Drilling apparatus according to claim 3 in which said triggering means comprises means for effecting disengagement of said movable element and said means engageable by said movable element.

5. Drilling apparatus according to claim 3 in which said triggering means comprises means for effecting disengagement of said movable element and said means engageable by said movable element, and including means for automatically effecting reengagement of said movable element and said means engageable by said movable element when said movable element reaches a second predetermined position in its range of movement. 

1. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end of a conduit a bit, means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis of drilling, a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling, a first means urging said hammer in the direction of drilling, a second means for pulling said hammer against the force of said first means and for releasing said first means tO cause said hammer to impart a blow to said bit, wherein said second means comprises a linear fluid actuator, a cable having one end connected to said hammer, means for fastening the other end of the cable to the conduit and a reciprocable sheave movable by said actuator, said cable being wound around said sheave between said fastening means and said hammer.
 2. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end of a conduit, a bit, means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis of drilling, a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling, a first means urging said hammer in the direction of drilling, a second means for pulling said hammer against the force of said first means, and for releasing said first means to cause said hammer to impart a blow to said bit, wherein said second means includes a fluid actuator, means for pivotally mounting a first part of said actuator, cam release means mounted adjacent to said fluid actuator for releasing said second means, a follower on a second part of said actuator which is movable relative to said first part, said follower being engageable with said cam release means, and said follower and cam means being so related that said second part moves angularly about said pivotally mounting means as a result of interaction between said cam means and said follower through at least part of the range of operation of said actuator, and means engageable by said second part of said actuator for effecting withdrawal of said cable against the force of said spring means, the last-mentioned means being arranged to be disengaged by said second part of said actuator when said second part moves about said pivoting means through a predetermined angle.
 3. Drilling apparatus comprising a subassembly adapted to be connected at one end to one end of a conduit, a bit, means mounting said bit at the other end of said subassembly and allowing movement of said bit along the axis of drilling, a hammer within said subassembly adapted to impart a blow to said bit to move said bit sharply in the direction of drilling, a first means urging said hammer in the direction of drilling, a second means for pulling said hammer against the force of said first means, and for releasing said first means to cause said hammer to impart a blow to said bit, wherein said first means comprises a spring located within said subassembly, and said second means includes a linear fluid actuator comprising piston and cylinder element one of which elements is adapted to be connected at the other end of the conduit opposite said subassembly and the other element being movable with respect to said connected element through a range of positions, a cable connected to said hammer, means engageable by said movable element for pulling said cable in response to operation of said actuator to withdraw said hammer against the force of said spring, and triggering means for automatically and instantaneously releasing said cable and allowing movement of said hammer by said spring when the movable element of said actuator reaches a predetermined position in said range.
 4. Drilling apparatus according to claim 3 in which said triggering means comprises means for effecting disengagement of said movable element and said means engageable by said movable element.
 5. Drilling apparatus according to claim 3 in which said triggering means comprises means for effecting disengagement of said movable element and said means engageable by said movable element, and including means for automatically effecting reengagement of said movable element and said means engageable by said movable element when said movable element reaches a second predetermined position in its range of movement. 